全文获取类型
收费全文 | 884篇 |
免费 | 38篇 |
国内免费 | 5篇 |
专业分类
化学 | 656篇 |
晶体学 | 12篇 |
力学 | 2篇 |
综合类 | 1篇 |
数学 | 69篇 |
物理学 | 187篇 |
出版年
2023年 | 10篇 |
2022年 | 7篇 |
2021年 | 17篇 |
2020年 | 14篇 |
2019年 | 20篇 |
2018年 | 12篇 |
2017年 | 7篇 |
2016年 | 19篇 |
2015年 | 23篇 |
2014年 | 27篇 |
2013年 | 51篇 |
2012年 | 52篇 |
2011年 | 55篇 |
2010年 | 31篇 |
2009年 | 33篇 |
2008年 | 58篇 |
2007年 | 61篇 |
2006年 | 80篇 |
2005年 | 58篇 |
2004年 | 48篇 |
2003年 | 40篇 |
2002年 | 34篇 |
2001年 | 13篇 |
2000年 | 13篇 |
1999年 | 9篇 |
1998年 | 15篇 |
1997年 | 13篇 |
1996年 | 8篇 |
1995年 | 6篇 |
1994年 | 7篇 |
1993年 | 7篇 |
1992年 | 15篇 |
1991年 | 7篇 |
1990年 | 6篇 |
1989年 | 2篇 |
1988年 | 4篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1985年 | 6篇 |
1984年 | 8篇 |
1983年 | 5篇 |
1982年 | 6篇 |
1981年 | 2篇 |
1980年 | 4篇 |
1979年 | 3篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1975年 | 1篇 |
1974年 | 2篇 |
1970年 | 1篇 |
排序方式: 共有927条查询结果,搜索用时 968 毫秒
81.
Tomoyuki MIYAZAKI Hiroki ABE Hiroyuki UCHIDA Takuya TAKAHASHI 《Proceedings of the Japan Academy. Series B, Physical and biological sciences》2021,97(1):1
Psychiatric and neurological disorders severely hamper patient’s quality of life. Despite their high unmet needs, the development of diagnostics and therapeutics has only made slow progress. This is due to limited evidence on the biological basis of these disorders in humans. Synapses are essential structural units of neurotransmission, and neuropsychiatric disorders are considered as “synapse diseases”. Thus, a translational approach with synaptic physiology is crucial to tackle these disorders. Among a variety of synapses, excitatory glutamatergic synapses play central roles in neuronal functions. The glutamate α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor (AMPAR) is a principal component of glutamatergic neurotransmission; therefore, it is considered to be a promising translational target. Here, we review the limitations of current diagnostics and therapeutics of neuropsychiatric disorders and advocate the urgent need for the promotion of translational medicine based on the synaptic physiology of AMPAR. Furthermore, we introduce our recent translational approach to these disorders by targeting at AMPARs. 相似文献
82.
Specific reactivity of 2,4,6-tri-tert-butylanilide anions and its application to benzylation reagent
The reaction of methyl iodide with an anilide anion prepared from 2,4,6-tri-tert-butylanilide and NaH in CH3CN gave N-methyl anilide (N-alkylation product) as a major product, while in the reaction of benzyl bromide with the anilide anion in DMF, O-benzyl imidate (O-alkylation product) was obtained with almost complete selectivity. The treatment of O-benzyl imidate with alcohols and carboxylic acids in the presence of trifluoromethane sulfonic acid gave benzyl ethers and benzyl esters, respectively. 相似文献
83.
Bis(trifluoromethanesulfonyl)amide (TFSA), hexafluorophosphate (PF(6)(-)), and iodide salts of 1-ferrocenyl-3-alkylimidazolium were prepared and their thermal and physical properties, including the dependence on alkyl chain length (methyl-hexadecyl), were investigated. The TFSA salts were highly viscous ionic liquids with melting points around room temperature. 1-Ferrocenyl-4-methyltriazolium salts were also prepared for comparison. The ferrocenylimidazolium and ferrocenyltriazolium cations showed redox waves for both the ferrocenyl moiety and the azolium moiety and exhibited corresponding charge-transfer bands at around 330 nm, which were analyzed using the Marcus-Hush model. Crystal structure determinations at low temperature revealed that the PF(6) and iodide salts form layerlike structures composed of ionic layers of the charged moieties. The TFSA salt exhibited short hydrogen-bond-like intermolecular contacts between the hydrogen atoms of the cation and oxygen atoms of the anion. 相似文献
84.
Satoshi Motodate Takuya Kobayashi Mikio Fujii Prof. Tomoyuki Mochida Dr. Taichi Kusakabe Shigeki Katoh Prof. Hiroyuki Akita Prof. Keisuke Kato 《化学:亚洲杂志》2010,5(10):2221-2230
Bis(oxazoline)‐palladium(II) catalyzed carbonylation of homopropargyl alcohols afforded acyclic methoxyacrylate 2 and 6‐membered lactone 3a , 3b , 3d , 3e , 3f , 3g , 3h , 3i , 3j , 3k in good combined yield. In the case of propargyl alcohols, 5‐membered lactones 3p , 3q , 16 were obtained in moderate yields. The one‐pot synthesis of kawa lactones 3a , 3r , 3s and formal synthesis of dihydroxycystothiazole A and dihydroxycystothiazole C are presented. To elucidate the stereochemistry of (+)‐annularin G and (?)‐annularin H, the first asymmetric syntheses of these natural products were achieved. 相似文献
85.
86.
Tomoyuki Miyazawa Haruka Abe Takayuki Suzuki Yosuke Togashi Kazuhiro Koshiji Yuki Nonaka 《Journal of carbohydrate chemistry》2013,32(5):252-266
We evaluated the potential of a linear β-1,3-glucan (curdlan) as a starting material to access C6-modified glucose derivatives and found that 6-bromo-6-deoxyglucose, 6-azide-6-deoxyglucose, and 6-acetamido-6-deoxyglucose could be readily prepared from curdlan through its C6-selective and quantitative modifications and subsequent acid-catalyzed hydrolysis. 相似文献
87.
88.
Using the57Fe conversion electron Mössbauer spectroscopy (CEMS), the structural and compositional changes at near surface of the amorphous Fe-13%B-9%Si and Fe-15%Cr-9%Ni stainless steel specimens have been clarified after the bombardment of 25kV accelerated He+ ions. 相似文献
89.
4-(3,17Beta-dihydroxyestra-1,3,5(10)-trien-6alpha- and 6beta-yl)amino-7-nitro-2,1,3-benzoxadiazoles have been synthesized and characterized as fluorescent probes for use in a receptor assay and/or a homogeneous immunoassay for estradiol. The fluorescence intensities are strongly dependent upon the solvent polarity used. The intensities in water were reduced to less than 1% of those in ethyl acetate, and a blue shift was also observed in polar solvents. The quenched fluorescence in aqueous solution was recovered by adding bovine serum albumin or an anti-estradiol antibody. Adding intact estradiol inhibited the fluorescence recovered by the antibody. 相似文献
90.
S. Nasu M. Yoshida Y. Oda T. Kohara T. Shinjo K. Asayama F. E. Fujita S. Katsuyama Y. Ueda K. Kosuge 《Hyperfine Interactions》1991,66(1-4):417-421
The57Co emission Mössbauer spectra from YBa2Cu3O6.92 (1-2-307) and YBa2Cu3O6.00 (1-2-306) have been measured and compared with the57Fe absorption spectra from YBa2Cu2.95Fe0.05O7?δ in order to clarify decisively the site assignments for the57Fe quadrupole-split doublets in these compounds. Mössbauer spectra obtained from both specimens consist of four components whose hyperfine interaction parameters well agree with each other. It is shown that the Co and Fe atoms mainly substitute at Cu1 chain sites in 1-2-307, but in 1-2-306 the Co atoms occupy randomly the Cu2 plane sites and indicate magnetically-split sextet which converts to a paramagnetic doublet of S-state Fe3+ in 1-2-307 by a post-annealing in O2 gas. 相似文献